Conventionally, there is proposed a technique of applying a transmission type screen using microlens arrays to a head-up display and a laser projector. In case of using such a transmission type screen, there is such an advantage that influence by speckle noise can be suppressed, in comparison the case of using a diffuser panel. For example, Patent Reference 1 proposes an image forming apparatus which uses a laser light as a light source, and which includes a laser projector for projecting an image formed by arranging a plurality of pixels, and a microlens array of a plurality of arranged microlens. In case of using the microlens array, the incident light can be appropriately dispersed and necessary diffusion angle can be freely designed.
On the other hand, Patent Reference 2, Patent Reference 3 and Non-Patent Reference 1 propose configuring a screen by two microlens arrays or two diffraction gratings, for example. Particularly, Non-Patent Reference 1 discloses that uneven luminance tends to occur when a single microlens array is used, but such uneven luminance can be suppressed by using two microlens arrays.